PC12 cells have been used as a model system to examine the cellular and molecular mechanisms that govern neuronal differentiation. These cells respond to nerve growth factor (NGF) and acquire the properties of sympathetic neurons. Using PC12 cells, I have observed that ethanol possesses the capability of synergizing with suboptimal concentrations of NGF to induce early neurite extension and subsequent differentiation. Preliminary studies indicate alterations in both protein kinase C and cAMP systems as targets for the effects of ethanol. The long term objective is to develop an understanding of the mechanism by which ethanol interacts with transmembrane signalling pathways to promote gene expression and subsequent differentiation. The specific aims are therefore to define conditions by which ethanol synergizes to promote differentiation by use of pharmacological agents with known specificity and correlate the presence or absence of neurites with indices for differentiation and expression of NGF-specific genes. I propose to detail the contribution of signal transducing pathways which interact to communicate the ethanol transmembrane signal by: a) examining protein kinase C and specifically explore alterations in the isoforms of this kinase brought about by both acute and chronic ethanol exposure; b) analyze activation pathways which either precede PKC activation, ie 'PI-turnover', are a result of PKC activation, i.e. coactivation of other kinase systems such as MAP2 and S6; c) correlate the activation of the adenylate cyclase system as a potential 'cross-talk' regulator between signal transducing pathways; and lastly, d) examine the phosphorylation of tyrosine hydroxylase-as a convergent substrate for multiple kinases.